To determine the molecular role of MHC class II alleles in susceptibility to EBA, the HLA-DRB, DQA genes and products will be studied by RFLP analysis, gene amplification and sequencing and by serologic subtyping. The data will be analyzed and compared with matched healthy controls to determine whether any HLA nucleotide sequences and deduced amino acid sequences of polymorphic regions are associated are common to the DR2, DQ haplotypes response to the specific epitope on the noncollagenous part of collagen type VII.